1. Field of the Invention
The present invention relates to a light emitting apparatus for color display using a wheel and a projector which is provided with the light emitting apparatus.
Priority is claimed on Japanese Patent Application No. 2004-200267, filed Jul. 7, 2004, the content of which is incorporated herein by reference.
2. Description of Related Art
Although, conventionally, various types of projectors of which projecting types differ are offered, as the projectors being common at present, a liquid crystal type of liquid crystal projector or a Digital Light Processing (hereinafter, abbreviated as DLP, which is a registered trademark) type of DLP projector is mainstream.
The liquid crystal projector uses, for example, three transmission liquid crystals of red color (R), green color (G), and blue color (B), and performs magnification projection while lighting the transmission liquid crystals from the rear; therefore adjustment is easy, and miniaturization and weight saving can be attained. Moreover, in the DLP projector, a plurality of minute movable mirrors which are provided in a Digital Micromirror Device (hereinafter, which is abbreviated as DMD) are moved at the speed of not less than several ten thousands of cycles per second, and thereby the image is formed, in addition to the advantage of the liquid crystal projector, the advantage can be obtained in which the decrease of the light is low, and thereby the light contrast can be obtained, a high-precision image which is seamless can be reproduced at high-brightness, high-resolution image display in which uniformity of the brightness is excellent, and stability is high can be carried out, and defects are unlikely to occur, and the like.
Here, a general constitution of the DLP projector is shown in FIG. 21 and FIG. 22.
The DLP projector 100 is provided with a lamp 101 which emits white color the light, red color (R), green color (G), and blue color (B) of color filters 103a, 102b, and 102c, a color wheel 102 which is rotated and driven by a motor 103, an integrator rod 104 which reduces the lighting unevenness of the light which passes through the color filters 102a, 102b, and 102c, and TIR (Total Internal Reflection) prism 107 in which the light which passed through the integrator rod 104 is entered into the DMD 105, and the image which is modulated by the DMD 105 is emitted to the projection lens 106.
After the white light which is emitted from the lamp 10 is emitted as the red color (R), the green color (G), and the blue color (B) of light in a time series by the color wheel 102, the light thereof is entered into the integrator rod 104. Furthermore, each color of light which has passed through the integrator rod 104 (in this case, the lighting unevenness of each color of light is lost) is performed a whole reflection in the TIR prism 107, and is entered into the DMD 105. After the light which is entered into the DMD 105 is modulated by the image data according to each color, the light is successively entered into the projection lens 106 via the TIR prism 107, again, and is projected as the color image on the screen (not shown in the figure).
Moreover, as a representational example of the lamp 101 which constitutes the projector 100, a spectral property of a very-high-pressure mercury lamp is shown in FIG. 23, and a chromaticity diagram of each light in the case in which the light of the very-high-pressure mercury lamp passes through a predetermined color filter is shown in FIG. 24. In addition, a horizontal axis in FIG. 23 shows the wavelength λ (unit is nm) of the light, and a longitudinal axis shows the relative intensity S.
As shown in FIG. 23, the very-high-pressure mercury lamp has the feature of having the strong relative intensity S near almost 450 nm (blue color) of wavelength λ, almost 550 nm (green color) of wavelength λ, and almost 590 nm (orange color) of wavelength λ, and on the other hand, not having the strong relative intensity S in the red component in the range of 600 to 700 nm of wavelength λ.
Therefore, when the very-high-pressure mercury lamp is used, in the case of designing the red color (R) of the color filter, the design is performed by using both the orange color of the wavelength component of the light of which the peak is near almost 590 nm and the width range of wavelength component which is 600 to 700 nm. As a result, a color expression range as shown by a dotted line in FIG. 24 is obtained.
As mentioned above, because the red color (R) is expressed using the orange color of the wavelength component of the light, as shown in FIG. 24, the area occurs in which the color expression cannot be carried out. That is, in the projection image using the very-high-pressure mercury lamp, a disadvantage occurs in that the reproduction of a part of the reddest color, the purplish red, or the like is difficult.
On the other hand, as a light emitting diode (LED), at present, a high power LED emitting at highbrightness, and the like are developed and provided, and further, various wavelengths of single wavelength LED, and the like are provided. Then, in order to solve the above-mentioned problem, the hybrid type of various apparatuses are beginning to be offered in which the LED light source is added to the lamp light source such as the very-high-pressure mercury lamp, and the like.
For example, as one example, the projection type of display apparatus is known in which the light from the red color (R) of light emitting diode is entered into a liquid crystal panel for the red via the lens array, after the optical image from the liquid crystal panel for the red and the blue color (B) and the green color G) of the optical image emitted from the lamp are composited by the compositing prism, the composite image is displayed on the screen by the projection lens (Patent Document 1: Japanese Unexamined Patent Application, First Publication No. 2000-305040).
Moreover, as the other example, a head portion equipping type of display apparatus is known in which the blue color (B) of an image is displayed by the lamp light source, the red color (R) and the green color (G) of images are displayed by the light emitting diode panel, the images thereof are composited by a polarization beam splitter, and the color image is obtained (for example, Patent Document 2: Japanese Unexamined Patent Application, First Publication No. H6-141262).
Moreover, as the other example, an image display apparatus is known in which, after the light emitted from the lamp and the red color (R) of light emitted from the leaser light source are composited by the light composition unit such as a reflection type of hologram element, a dichroic prism, or the like, each color (the red color (R), the green color (G), and the blue color B) of light is led to the liquid crystal display panel, the image light according to each color is generated, each image light thereof is composited again, and the composite image light is displayed on the screen (Patent Document 3: Japanese Unexamined Patent Application, First Publication No. 2002-296680).
Moreover, in the Patent Document 3, the light emitted from the lamp and the light emitted from the light emitting diode are composited by the dichroic prism, the composite light is separated into the red color (R), the green color (G), and the blue color (B) of light in the time series by the color wheel, is led to the DMD, and is displayed as the color image on the screen.
Furthermore, as the other example, the light emitting apparatus is known in which a green color (G) of beam emitted from the lamp and red color (R) and blue color (B) of beams emitted from the LED element are composited by the dichroic prism, each color of light which is composited is modulated according to each color by the liquid crystal panel, and is displayed as the image on the screen (for example, Patent Document 4: Japanese Unexamined Patent Application, First Publication No. 2003-263902).
Moreover, when the green color (G) of beam is obtained by the light emitted from the lamp, the light emitting apparatus is arranged between the lamp and the dichroic mirror, and uses a disc shape, that is, a wheel shape of color filter which is provided with the green color (G) of filter portion and the shading portion which shades the light. That is, the green color (G) of the beam can be obtained during a predetermined time by rotating the color filter. Moreover, when shading the light from the lamp in the shading portion, the red color (R) and the blue color (B) of beams are lightened while shifting the timing by the LED element. Thereby, the red color (R), the green color (G), and the blue color (B) of beams can be successively entered into the liquid crystal panel via the composition prism in the time series.